Mansoureh Mozaffari; Hossein Ghaffari Setoubadi; Hamid Reza Gazor; Jaber Soleimani
Abstract
Hot air drying is the most common method used to dry agricultural products; this method is time consuming and has high energy consumption. Also, due to the rapid drying of the product surface in this method, the distribution and transferring of heat and moisture inside the product is relatively uneven. ...
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Hot air drying is the most common method used to dry agricultural products; this method is time consuming and has high energy consumption. Also, due to the rapid drying of the product surface in this method, the distribution and transferring of heat and moisture inside the product is relatively uneven. In fruits, such as apricots, skin of the fruit has a controlling and inhibitory effect on the drying process. Therefore, using some combination methods to dry fruits such as apricots, can reduce drying time and energy consumption. In the present study, a convection dryer was equipped with an infrared radiation system. The effect of hot air and infrared combination in different strategies on apricot drying was evaluated and compared. Experiments were conducted with hot air and infrared treatments alone, simultaneously and in a combination of two-stage and intermittent infrared in a combined dryer on a laboratory scale. The hot air temperature was 65 ° C, the velocity of hot air was 1.5 m/s and the power of infrared lamps was 400 watts. The results showed that the drying time, energy consumption and effective moisture penetration coefficient were significantly affected by the treatments. Midili et al.'s model was able to describe well the drying behavior of apricots for all the different combination states under investigation.
Hamid Reza Gazor; Mohammad Reza Alizadeh
Abstract
Long time processing, high energy consumption and non-uniformity in layers moisture are common problems in paddy drying using conventional batch type dryer, leading to increase the chance of kernel breaking during milling process. In this research, drying time, grains moisture content change and energy ...
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Long time processing, high energy consumption and non-uniformity in layers moisture are common problems in paddy drying using conventional batch type dryer, leading to increase the chance of kernel breaking during milling process. In this research, drying time, grains moisture content change and energy consumption of a newly rotary dryer were compared with that of a conventional batch type dryer for paddy (Hashemi variety) drying. Besides, quality parameters as hulling milling ratio, head rice yield and white rice breaking percent were studied in paddy dried using both dryers. All Experiments were done triplicate and data analyzed using T- student method in 5% probability. Results showed that newly rotary dryer caused uniformity in drying processes and cleaning of dried paddy; but, in conventional batch type dryer, because of environmental warm air around it, drying time and energy consumption were about 9 and 8.9 percent, respectively, less than what were calculated in newly rotary dryer. Specific energy consumption for paddy moisture evaporation was 13.5 MJ/kgH2O and it was about 11 percent less than that in rotary dryer. The difference of paddy moisture contents and temperatures in top and lower part of layers of batch type dryer were 2 percent and 6 °C respectively. Milling ratio increased 3.8 percent when rotary dryer was used. Rotary dryer did not have significant effect on paddy hulling. The main effect of using rotary dryer occurred on head rice yield and it was increased about 7.5 percent, comparing with batch dryer. Using rotary dryer caused 7.8 percent decrease in broken kernels, comparing with conventional batch type dryer.
Hamidreza Gazor; Mohammadreza Alizadeh; Mohammad Younesi
Abstract
In this research, operational process and energy consumption of paddy milling factories in three categories: conventional system (Engelberg Machine for hulling and whitening), semi modern system (Rubber roll dehusker and Engelberg whitener), modern system (Rubber roll husker and abrasive whitener) were ...
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In this research, operational process and energy consumption of paddy milling factories in three categories: conventional system (Engelberg Machine for hulling and whitening), semi modern system (Rubber roll dehusker and Engelberg whitener), modern system (Rubber roll husker and abrasive whitener) were investigated in Mazandaran province of Iran. Besides, milling efficiency, Degree of hulling, breakage percent of brown rice and white rice, degree of whitening, and quality factors gelatinization index, percentage of elongation and amylose of cooked rice were studied. Analysis of results indicated that no significant difference exist in degree of milling among conventional, semi modern and modern systems. The changes in the milling efficiency ranged between 62.45 to 63.58 percents. The milling systems had significant difference in hulling operation. Using rubber roll de husker decreased grain breakage and adding gravity separator to dehulling process increased dehulling to 96 percent. Engelberg de husker and whitener had significant effect on brown rice breakage and whitening than Rubber roll dehusker respectively. Results showed yhat, modern rice milling system had less harmful effects on rice than other systems. Rice milling systems did not have significant effect on amylose and gelatinization index of white rice. The parameters and gelatinization index varied in treatments from 21 to 22 percent and 3.97 to 3.99 respectively. Using of conventional milling system has more effect on cooked rice elongation percent than other systems. Results showed that, drying and milling of paddy consume 683.8 and 158.4 MJ thermal and electrical energy per ton respectively.
